%ID/gm=Percent injected dose per gram, which is the most common measure of tracer biodistribution. Note that PET data are intrinsically in units of Activity/Volume (e.g. Bq/cc). If a tissue density of 1 gm/mL is assumed, then the PET data can be converted directly to Bq/gm. A caveat is that lung tissue has a density of about 0.5 gm/mL. Since the data are already presented per unit weight, the PET activity (ACT, e.g. nCi/cc) only needs to be normalized for the injected dose (DOSE) to get %ID/gm. From ACT and DOSE, the SUV is given by:

%ID/gm=ACT/DOSE*100